Broadband current transformer test method, device, equipment and medium

Abstract

The invention discloses a broadband current transformer testing method, device and equipment and a medium, and relates to the technical field of transformer verification. First, first frequency signals of standard current and current to be measured are synchronously obtained, the frequency of the signal to be measured is tracked in real time through a high-speed comparator, and a second frequency signal is accurately generated through the digital frequency synthesis technology. The method comprises the following steps: firstly using a high-order digital filter to measure a broadband signal frequency spectrum, then using an analog mixing technology to shift the signal frequency spectrum, generating a composite signal containing a difference frequency component and a sum frequency component, finally accurately filtering the sum frequency component through the high-order digital filter, and only measuring the difference frequency signal to obtain a ratio error and an angular error of the broadband signal. By converting the measurement of the broadband signal into the measurement of the fixed low-frequency signal, the technical bottleneck of direct sampling in a high-frequency band in the traditional sampling technology is broken through, and the actual measurement ratio error and angular error precision of the broadband current transformer is effectively improved. The system power consumption and the hardware cost are significantly reduced while the measurement precision is ensured, and the reliability and the accuracy of the broadband current transformer test are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer calibration, and in particular to a wide-band current transformer testing method, device, equipment and medium. Background Art

[0002] Currently, direct sampling is the primary method for testing wideband current transformers. This technique first converts the standard current signal and the current signal to be measured, output by the wideband current transformer, into digital signals. These signals are then simultaneously sampled using a dual-channel analog-to-digital converter. However, this direct sampling method has inherent limitations: due to the performance limitations of the analog-to-digital converter chip, it is difficult to achieve high sampling rates while maintaining high sampling accuracy. This inconsistency can lead to loss or distortion of signal details during testing, compromising the accuracy and reliability of the final test results. Summary of the Invention

[0003] In view of this, the present invention provides a wide-band current transformer testing method, device, electronic device and medium to address the inherent limitations of the direct sampling method, which is mainly reflected in the difficulty of the analog-to-digital conversion chip to simultaneously take into account the sampling accuracy and sampling rate. This contradiction will lead to the loss or distortion of signal details during the test process, thereby affecting the accuracy and reliability of the final test results.

[0004] In a first aspect, a method for testing a wide-band current transformer is provided, the method comprising: Acquire a standard current signal, a current signal to be measured of a wide-band current transformer, and first frequency signals of the standard current signal and the current signal to be measured; Based on the first frequency signal, a second frequency signal is generated by frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference; Generate a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, and filter out the sum frequency component in the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal; Based on the first low-frequency signal and the second low-frequency signal, a ratio difference and an angle difference of the current signal to be measured relative to the standard current signal are determined.

[0005] In a second aspect, a wide-band current transformer testing device is provided, the device comprising: An acquisition module, configured to acquire a standard current signal, a current signal to be measured of a wide-band current transformer, and a first frequency signal of the standard current signal and the current signal to be measured; A first generating module is configured to generate a second frequency signal based on the first frequency signal by a frequency synthesis technique, wherein the second frequency signal is equal to a difference between the first frequency signal and a preset frequency difference; a second generating module, configured to generate a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, and to filter out the sum frequency component in the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal; The determination module is used to determine the ratio difference and the angle difference of the current signal to be measured relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal.

[0006] In a third aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned wide-band current transformer testing method when executing the computer program.

[0007] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned wide-band current transformer testing method are implemented.

[0008] In the solution implemented by the above-mentioned wideband current transformer testing method, device, electronic device and storage medium, the first frequency signal of the standard current and the current to be measured is first obtained synchronously, the frequency of the signal to be measured is tracked in real time by a high-speed comparator, and the second frequency signal is accurately generated by digital frequency synthesis technology. Subsequently, the signal spectrum is shifted by analog mixing technology to generate a composite signal containing a difference frequency component and a sum frequency component. Finally, a high-order digital filter is used to accurately filter out the sum frequency component, and only the difference frequency signal is measured to obtain the ratio difference and angle difference parameters of the wideband signal. By converting the measurement of the wideband signal into the measurement of a fixed low-frequency signal, the technical bottleneck of direct sampling of the traditional sampling technology in the high frequency band is broken through, and the accuracy of the measured ratio difference and angle difference of the wideband current transformer is effectively improved. While ensuring the measurement accuracy, the system power consumption and hardware cost are significantly reduced, ensuring the reliability and accuracy of the wideband current transformer test in the smart grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings: Figure 1 1 is a flow chart of a method for testing a wide-band current transformer according to an embodiment of the present invention; Figure 2 is a structural schematic diagram of a wide-band current transformer testing system according to an exemplary embodiment; Figure 31 is a schematic structural diagram of a wide-band current transformer testing device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be understood that the drawings in the present invention are only for the purpose of illustration and description and are not used to limit the scope of protection of the present invention.

[0011] In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in the present invention illustrate operations implemented according to some embodiments of the present invention. It should be understood that the operations in the flowcharts may be implemented out of sequence, and steps that do not have a logical contextual relationship may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the present disclosure, may add one or more other operations to the flowcharts, or may remove one or more operations from the flowcharts.

[0012] In addition, the embodiments described in the present invention are only some of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0013] It should be noted that the term "comprising" will be used in the embodiments of the present invention to indicate the presence of the features subsequently claimed, but does not preclude the addition of other features. It should also be noted that similar reference numerals and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures.

[0014] The following is a detailed description of this case with reference to the relevant drawings in the specification.

[0015] See also Figure 1 This embodiment of the present invention provides a method for testing a wide-band current transformer, which specifically includes the following steps: S10: Acquire a standard current signal, a current signal to be measured of a wide-band current transformer, and first frequency signals of the standard current signal and the current signal to be measured.

[0016] It is understandable that the execution subject of the present invention may be a wideband current transformer test device, or a terminal or a server, which is not limited here. The embodiment of the present invention is described by taking a server as the execution subject as an example.

[0017] In this step, the standard current signal is a known, accurate current signal used as a benchmark during the calibration process. It is typically generated by a high-precision standard current source and provides a measurement reference. The current signal to be measured is the output signal of the broadband current transformer being measured. Because the standard current and the current to be measured have the same frequency characteristics, a frequency measurement device can be used to extract the frequency value from both signals, recording it as the first frequency signal.

[0018] S20: Based on the first frequency signal, generate a second frequency signal through a frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference.

[0019] In this step, frequency synthesis technology can generate multiple frequency signals based on the input reference frequency signal. This technology processes the first frequency signal to generate a new frequency signal, recorded as the second frequency signal. The frequency of the newly generated signal strictly satisfies the relationship: second frequency signal = first frequency signal - preset frequency difference.

[0020] Optionally, the preset frequency difference can be set to 10Hz. By setting a fixed frequency difference of 10Hz, the frequency difference between the first and second frequency signals is strictly locked at 10Hz, achieving the conversion process of high-frequency signals to low-frequency signals. This frequency conversion method effectively reduces the difficulty of signal processing, making low-frequency signals easier to accurately test and quantify, thereby significantly improving the measurement resolution and accuracy, and ensuring the reliability of the final measurement results.

[0021] In one embodiment of the present application, a specific second frequency signal generation scheme is provided. In S20, the second frequency signal is generated based on the first frequency signal by frequency synthesis technology, which specifically includes the following steps S21-S23: S21: Tracking the standard current signal through an analog comparator to generate a square wave signal synchronized with the first frequency signal.

[0022] In this step, the standard current signal is converted into a square wave signal with the same frequency as the first frequency signal through an analog comparator. This square wave signal serves as the reference clock input of the direct frequency synthesizer (DDS), providing a synchronization reference for the system, thereby ensuring that the second frequency signal output by the DDS maintains strict frequency correlation with the original input signal.

[0023] S22: The square wave signal is input to the direct frequency synthesizer, and the system clock frequency signal is generated through the internal clock multiplication function of the direct frequency synthesizer.

[0024] In this step, after receiving a square wave input synchronized with the first frequency signal, the DDS uses its built-in frequency multiplication circuit to multiply the frequency of the input square wave signal, thereby generating a high-precision system clock frequency signal. This effectively ensures excellent accuracy and stability during the frequency synthesis process.

[0025] S23: Generate a second frequency signal based on the system clock frequency signal and a preset frequency division setting value of the direct frequency synthesizer.

[0026] In this step, a frequency division setting value is preconfigured in the direct frequency synthesizer according to the preset frequency difference. The direct frequency synthesizer performs precise frequency division processing based on the system clock frequency signal through its internal frequency division circuit according to the preset frequency division setting value, and ultimately outputs the desired second frequency signal.

[0027] In the above manner, through the coordinated work of the analog comparator and the direct frequency synthesizer, the standard current signal is subjected to waveform conversion, frequency multiplication and frequency division processing in sequence, and finally the second frequency signal is accurately generated.

[0028] In one embodiment of the present application, a specific second frequency signal verification scheme is provided. After S20, that is, after the second frequency signal is generated by a direct frequency synthesizer based on the first frequency signal, the following steps are further included: Obtaining a difference between the first frequency signal and the second frequency signal; Determine whether the difference is equal to the preset frequency difference; If the difference is not equal to the preset frequency difference, the second frequency signal is adjusted by adjusting the preset frequency division setting value until the difference between the first frequency signal and the second frequency signal is equal to the preset frequency difference.

[0029] In this embodiment, to ensure that the frequency difference between the first frequency signal and the second frequency signal is strictly locked to the preset frequency difference, the frequency value of the second frequency signal is subtracted from the frequency value of the first frequency signal to obtain the difference between the two, and the difference is compared with the preset frequency difference: if the two are consistent, it means that the current frequency relationship meets the design specifications; if there is a deviation, adjustment is required. Since the direct frequency synthesizer generates the second frequency signal by performing a frequency division operation based on the system clock frequency and the preset frequency division setting value. When the measured difference does not match the preset frequency difference, the output of the second frequency signal is accurately corrected by dynamically adjusting the size of the preset frequency division setting value until the difference between the first frequency signal and the second frequency signal completely matches the preset frequency difference, thereby achieving high-precision frequency control.

[0030] S30: Generate a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, and filter out the sum frequency component in the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal.

[0031] In this step, the standard current signal is mixed with the second frequency signal. The sum frequency component is then filtered out, and the difference frequency component is extracted as the first low-frequency signal. Using the same processing method, the current signal to be measured is mixed with the second frequency signal, retaining the difference frequency component to obtain the second low-frequency signal.

[0032] In one embodiment of the present application, a specific low-frequency signal generation scheme is provided. In S30, based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, a first low-frequency signal and a second low-frequency signal are generated. The scheme specifically includes the following steps S31-S32: S31: Based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, obtain a first mixed analog signal and a second mixed analog signal through analog mixing technology, wherein the mixed analog signal includes a difference frequency component and a sum frequency component.

[0033] In this step, the standard current signal is mixed with the second frequency signal to produce a first mixed analog signal. Similarly, the current signal to be measured is mixed with the second frequency signal to produce a second mixed analog signal. During the mixing process, when two signals of different frequencies interact with each other, a difference frequency component and a sum frequency component are generated. During the mixing process, the interaction of the signals produces two main frequency components: a difference frequency component (with a frequency value equal to the first frequency signal minus the second frequency signal) and a sum frequency component (with a frequency value equal to the first frequency component plus the second frequency signal).

[0034] By the above method, the high-frequency standard current signal and the current signal to be measured are converted into a mixed analog signal containing difference frequency and sum frequency, which is convenient for subsequent signal processing and analysis.

[0035] In one embodiment of the present application, a specific mixed analog signal generation scheme is provided. In S31, based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal, a first mixed analog signal and a second mixed analog signal are obtained by analog mixing technology. The scheme specifically includes the following steps S311-S312: S311: Multiply the first frequency signal of the standard current signal by the second frequency signal to obtain a first mixed analog signal corresponding to the standard current signal.

[0036] In this step, an analog multiplier is used to linearly mix the first frequency signal and the second frequency signal of the standard current signal to generate a first mixed analog signal.

[0037] S312: Multiply the first frequency signal of the current signal to be measured by the second frequency signal to obtain a second mixed analog signal corresponding to the current signal to be measured.

[0038] In this step, an analog multiplier is used to linearly mix the first frequency signal and the second frequency signal of the current signal to be measured to generate a second mixed analog signal.

[0039] S32: Performing analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal, and filtering out the sum frequency component based on a preset sampling rate to obtain a first low-frequency signal corresponding to the standard current signal and a second low-frequency signal corresponding to the current signal to be measured.

[0040] In this step, the analog-to-digital conversion (ADC) realizes the discretization processing of the analog signal into a digital signal. When the first mixed analog signal and the second mixed analog signal are digitized by the analog-to-digital converter respectively, a preset sampling rate is required to ensure the complete acquisition of the signal information. Since the sum frequency component in the mixed analog signal is significantly higher than the difference frequency component, the high-frequency sum frequency component can be effectively filtered out by a digital low-pass filter designed based on the preset sampling rate, thereby extracting the low-frequency difference frequency component corresponding to the standard current signal (i.e., the first low-frequency signal) and the low-frequency difference frequency component corresponding to the current signal to be measured (i.e., the second low-frequency signal).

[0041] By converting the standard current signal and the current signal to be measured into corresponding low-frequency signals in this way, it not only facilitates subsequent processing and analysis but also significantly reduces the amount of data and computational complexity. This effectively improves the efficiency and accuracy of signal processing while ensuring signal integrity.

[0042] In one embodiment of the present application, a specific low-frequency signal acquisition solution is provided. In S32, analog-to-digital conversion is performed on the first mixed analog signal and the second mixed analog signal, and high-frequency components are filtered out based on a preset sampling rate to obtain a first low-frequency signal corresponding to the standard current signal and a second low-frequency signal corresponding to the current signal to be measured. The solution specifically includes the following steps S321-S325: S321: Decompose the first mixed analog signal based on trigonometric identities to obtain a first difference frequency component and a first sum frequency component.

[0043] S322: Decompose the second mixed analog signal based on trigonometric identities to obtain a second difference frequency component and a second sum frequency component.

[0044] In steps S321-S322, based on the product-to-sum-difference principle of trigonometric functions, the first mixed analog signal is decomposed to obtain two characteristic frequency components: a first difference frequency component and a first sum frequency component. Similarly, based on the product-to-sum-difference principle of trigonometric functions, the second mixed analog signal is decomposed to obtain two characteristic frequency components: a second difference frequency component and a second sum frequency component.

[0045] S323: Perform analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal to generate a first digital signal and a second digital signal.

[0046] In this step, the analog-to-digital converter (ADC) discretizes and samples the analog input signal (the first mixed analog signal and the second mixed analog signal) at a fixed sampling period, and converts the sampled analog value into a digital code through quantization processing, thereby generating a first digital signal representing the standard current signal and a second digital signal representing the standard measured current signal, respectively.

[0047] In this way, accurate mapping of analog signals to digital domain is achieved.

[0048] S324: Downsample the first digital signal to a target rate through a digital filter, filter out the first sum frequency component of the first digital signal, and output a digital signal corresponding to the first difference frequency component, which is recorded as a first low-frequency signal.

[0049] In this step, downsampling refers to reducing the signal's sampling rate through digital filtering and decimation techniques. When downsampling the first digital signal, a digital filter first removes high-frequency components, then proportionally decimates the sample points, ultimately reducing the sampling rate to the target rate. This processing method significantly reduces the amount of data, lowering the system processing load and computational complexity. It also optimizes signal characteristics by removing redundant high-frequency components while retaining valid low-frequency information, thereby better meeting the requirements of subsequent low-frequency signal processing.

[0050] Furthermore, a digital low-pass filter is used to filter the signal in the frequency domain, effectively removing the first sum frequency component while fully preserving the digital signal characteristics corresponding to the first difference frequency component. This process outputs a first low-frequency signal that fully retains the amplitude and phase characteristics of the original difference frequency signal: the amplitude parameter characterizes the signal strength, while the phase parameter reflects the signal timing relationship. These two key parameters provide an important basis for subsequent precise signal analysis and processing.

[0051] By selectively processing the frequency domain in the above manner, the integrity of the signal features is ensured while optimizing the extraction of the signal features.

[0052] S325: Downsample the second digital signal to a target rate through a digital filter, filter out the second sum frequency component of the second digital signal, and output a digital signal corresponding to the second difference frequency component, which is recorded as a second low-frequency signal.

[0053] The digital signal includes the amplitude and phase information of the difference frequency signal.

[0054] In this step, the second digital signal is downsampled to reduce its sampling rate to the target rate, effectively reducing the data volume while meeting subsequent processing requirements. The second sum frequency component is then filtered out using a digital filter (such as a low-pass filter), accurately extracting the digital signal corresponding to the second difference frequency component—the second low-frequency signal. This signal fully preserves the amplitude, intensity, and phase timing characteristics of the second difference frequency signal, providing a reliable data foundation for subsequent precise signal analysis.

[0055] In this way, the mixed analog signal is converted into a low-frequency digital signal containing difference frequency information, which facilitates subsequent more accurate signal analysis and measurement.

[0056] S40: Determine a ratio difference and an angle difference of the current signal to be measured relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal.

[0057] In this step, in the performance test of the wide-band current transformer, the ratio difference and the angle difference are two key metrological parameters. The ratio difference represents the amplitude deviation between the current signal to be measured and the standard current signal. By analyzing the amplitude difference between the first low-frequency signal and the second low-frequency signal, the amplitude error of the current signal to be measured can be accurately calculated. The angle difference reflects the phase offset between the current signal to be measured and the standard current signal. By measuring the phase difference between the first low-frequency signal and the second low-frequency signal, the phase deviation of the current signal to be measured can be directly determined. Finally, based on the accurate measurement results of the ratio difference and the angle difference, the metrological stability and working performance of the wide-band current transformer can be effectively evaluated.

[0058] In one embodiment of the present application, a specific ratio difference and angular difference calculation scheme is provided. In S40, based on the first low-frequency signal and the second low-frequency signal, the ratio difference and angular difference of the current signal to be measured relative to the standard current signal are determined, which specifically includes the following steps S41-S44: S41: Extracting a first amplitude and a first phase of a first low-frequency signal.

[0059] S42: Extracting a second amplitude and a second phase of the second low-frequency signal.

[0060] In steps S41-S42, the first low-frequency signal, as a representation of the standard current signal after system processing, fully preserves the signal characteristics of the standard current signal. Using digital signal processing methods such as fast Fourier transform (FFT) or correlation algorithms, the amplitude and phase parameters of the first low-frequency signal can be accurately extracted from the first low-frequency signal, denoted as the first amplitude and first phase, respectively. These two parameters constitute the baseline reference values ​​of the standard current signal. Similarly, the second low-frequency signal represents the characteristics of the current signal under test after the same processing flow. Using the same algorithm, its corresponding second amplitude and second phase parameters can be extracted, fully reflecting the signal characteristics of the tested channel.

[0061] S43: Calculate the ratio difference based on the first amplitude and the second amplitude.

[0062] In this step, the ratio difference is used to measure the deviation of the amplitude of the signal of the detected channel relative to the amplitude of the standard current signal. The calculation formula is: .

[0063] Substituting the first amplitude and the second amplitude into the ratio difference calculation formula reflects the relative difference between the amplitude of the detected channel signal and the amplitude of the standard current signal.

[0064] S44: Calculate an angle difference based on the first phase and the second phase.

[0065] In this step, the angle difference is used to measure the degree of deviation of the phase of the detected channel signal relative to the phase of the standard current signal. The calculation formula is: Angle difference = second phase - first phase; Substituting the first phase and the second phase into the angle difference calculation formula can reflect whether the phase relationship between current and voltage meets the requirements.

[0066] By calculating the ratio difference and angle difference in the above manner, the difference between the detected channel signal and the standard current signal can be comprehensively evaluated, thereby accurately judging and calibrating the performance of the wideband current transformer.

[0067] It can be seen that in the above scheme, the first frequency signals of the standard current and the current to be measured are first obtained synchronously, the frequency of the signal to be measured is tracked in real time by a high-speed comparator, and the second frequency signal is accurately generated by digital frequency synthesis technology. Subsequently, the signal spectrum is shifted by analog mixing technology to generate a composite signal containing difference frequency components and sum frequency components. Finally, the sum frequency components are accurately filtered out by a high-order digital filter, and only the difference frequency signal is measured to obtain the ratio difference and angle difference parameters of the wideband signal. By converting the measurement of the wideband signal into the measurement of a fixed low-frequency signal, the technical bottleneck of direct sampling in the high-frequency band of traditional sampling technology is broken through, and the accuracy of the measured ratio difference and angle difference of the wideband current transformer is effectively improved. While ensuring the measurement accuracy, the system power consumption and hardware cost are significantly reduced, ensuring the reliability and accuracy of the wideband current transformer test in the smart grid.

[0068] In actual application scenarios, with the continued rapid growth in the scale of renewable energy power generation such as photovoltaic and wind power, and the grid connection of a large number of rectifier equipment and non-linear loads such as high-speed rail, harmonic currents with frequencies as high as 2kHz or even higher have appeared in the power system. The "double high" problem of high proportion of new energy access and high proportion of power electronic equipment application has become increasingly prominent, resulting in increasingly complex dynamic characteristics of the power grid and significantly increased measurement errors. The resulting inaccurate broadband electricity metering problem can easily lead to electricity settlement trade disputes. Both power quality assessment and electricity metering rely on the acquisition of secondary side signals of current transformers. Therefore, only by ensuring the accurate transmission of broadband signals by current transformers can the accuracy of measurement signals be guaranteed from the source. In order to ensure the accuracy of broadband current transformer test results, the present application proposes a broadband current transformer test system for implementing the above-mentioned broadband current transformer test method, such as Figure 2 Figure 2 shows the structure of a wideband current transformer test system. The wideband current transformer test system includes: a multi-channel AD synchronous conversion module U1, analog front-end drivers A1 and A2, analog multipliers M1 and M2, analog comparator A3, wideband shunts R1 and R2, a direct digital frequency synthesizer (DDS) U5, a DSP (Digital Signal Processor) processing module U2, an LCD display U3, a KEY keyboard module U4, and a resistor R3. The specific connections are as follows: The inputs of broadband shunts R1 and R2 are connected to the external current to be measured, Ix, and the standard current, Ib, respectively, through copper wires. The outputs of broadband shunts R1 and R2 are connected to the inputs of analog multipliers M1 and M2, respectively. The output of broadband shunt R2 is also connected to the input of analog comparator A3.

[0069] The output of analog comparator A3 is connected to the reference clock input CLKREF (Reference Clock) of direct digital frequency synthesizer U5. The clock output CLKOUT of direct digital frequency synthesizer U5 is converted into a voltage signal through resistor R3 and simultaneously connected to the inputs of analog multipliers M1 and M2. The low potential terminal (GND) of the voltage signal is grounded.

[0070] The outputs of the analog multipliers M1 and M2 are connected to the inputs of the analog front-end drivers A1 and A2, respectively, and their low potential terminals (GND) are grounded. The outputs of the analog multipliers M1 and M2 are connected to the inputs of the analog front-end drivers A1 and A2, respectively, and their low potential terminals are also grounded.

[0071] The output ends of the analog front-end drivers A1 and A2 are respectively connected to CH1 (channel 1) and CH2 (channel 2) of the multi-channel AD synchronous conversion module U1, and the low potential ends are grounded.

[0072] In the DSP processing module, the multi-channel A / D synchronous conversion module U1 communicates with the DSP processing module via an SPI interface. The direct digital frequency synthesizer U5 also connects to the DSP processing module's SPI interface via an SPI interface. The LCD display U3 connects to the DSP processing module via an AMC (Asynchronous Memory Bus) interface. The KEYpad module U4 exchanges data with the DSP processing module via six GPIO (General Purpose Input / Output) interfaces.

[0073] Wideband shunts R1 and R2 are used to achieve wideband conversion of high current to low voltage signals. In this embodiment, the conversion range is 0-1A input current. The operating frequency band is 50Hz-100kHz. The Fluke A40B-1A is used, achieving an actual accuracy of 50ppm.

[0074] The analog front-end drivers A1 and A2 match the analog multiplier output to the drive current and voltage of the multi-channel A / D synchronous conversion module U1. THD (total harmonic distortion) ≥ 120dB. The optional op amp OPA1632 (measured THD 130dB) is recommended.

[0075] Analog comparator A3, response time: ≤5μs, LM339 optional (actual switching time 1us).

[0076] The multi-channel synchronous AD conversion module U1 has an integral error of no less than ±0.01%, utilizes the sigma-delta AD principle, and has a built-in high-quality filter. This embodiment uses the 24-bit, 8-channel synchronous sigma-delta AD converter ADS1278, with a typical integral error of ±0.0003% and a maximum sampling rate of 128kSPS. The reference voltage used is the ADR441B, with a 2.5V reference voltage (temperature drift less than 3ppm).

[0077] The DSP processing module U2 has at least two SPI interfaces, six IO interfaces, and one AMC interface. It can optionally be composed of the ADI BF609 chip and its peripherals. The chip has a large number of built-in peripherals, including one SPI interface, 16 general-purpose IO ports, an AMC interface (asynchronous memory interface), 256MBYTE DRAM, and is used to implement the core algorithms, task scheduling, display, and input of the embodiments of this application.

[0078] Human-computer interaction module: LCD display screen U3, interface mode: AMC bus drive. KEY keyboard module U4 is a simple keyboard with a 6-key layout input to the 6 IOs of the DSP processing module U2, used to operate the start and end of the test and input the frequency to be tested.

[0079] Direct digital frequency synthesizer U5 is used for precise frequency generation (f1 to f1-10Hz) and clock multiplication (≥64 times). The AD9913 chip is optional.

[0080] The current-voltage conversion resistor R3 is a 1kΩ high-precision resistor with a temperature drift index of 10ppm.

[0081] When using a wide-band current transformer for wide-band current transformer testing, the wide-band current transformer testing steps are as follows: First, the operator inputs the broadband frequency f1 to be measured (the test current source frequency) through keyboard module U4. DSP processing module U2 controls the DDS output of the corresponding frequency f2 via the SPI interface. DSP processing module U2 then acquires data from multi-channel synchronous A / D converter module U1 at a 40Hz sampling rate via the SPI interface. U1 automatically filters out the (f1 + f2) frequency components at this 40Hz sampling rate. DSP processing module U2 then calculates the ratio and angular difference of broadband signal f1 in real time, completing measurement data analysis and processing. Finally, the measurement results are output to LCD display U4 via the AMC bus interface.

[0082] Specifically, the working principle of the broadband current transformer test system is as follows: Assume the standard current signal is: ; (1) Wherein, Ib is the instantaneous value of the standard current signal; IbA is the amplitude of the standard current signal; f1 is the first frequency signal of the standard current signal; t is the time variable; is the initial phase angle of the standard current signal.

[0083] Assume that the current signal to be measured is: ; (2) Wherein, Ix is the instantaneous value of the current signal to be measured; IxA is the amplitude of the current signal to be measured; f1 is the first frequency signal of the current signal to be measured; t is the time variable; is the initial phase angle of the current signal to be measured.

[0084] The calculation formula for the wide-band current transformer ratio difference is: ; (3) Where ferr is the ratio difference.

[0085] The calculation formula for the wide-band current transformer angle difference is: ; (4) in, is the angular difference.

[0086] Analog comparator A3 converts the input analog signal into a square wave signal with the same frequency (f1) as the reference clock source of the DDS.

[0087] The DDS internally multiplies the input clock of f1 by N times to form the internal clock frequency of the system fsysclk = N × f1.

[0088] Then the frequency f2 of the DDS clock output CLKOUT is: ; (5) Where f2 is the second frequency signal output by DDS; FTW is the preset frequency division setting value of DDS; N is the clock multiplication factor inside DDS; f1 is the first frequency signal; 2 32 is the 32-bit frequency resolution of DDS; fsysclk is the internal clock frequency of DDS.

[0089] Let f2 = f1-10, that is, set the DDS output frequency f2 to be 10Hz less than the input frequency f1. Then the frequency relationship is: ; (6) Therefore, the FTW calculation formula is: ; (7) The frequency control mechanism based on formula (7) can accurately set the DDS output frequency f2 = f1-10Hz.

[0090] Assume that the reference signal output by DDS is: ; (8) Among them, Uref is the instantaneous value of the reference signal output by DDS; UrefA is the amplitude of the reference signal; is the initial phase of the reference signal.

[0091] Then the output waveform of analog multiplier M1 is the product of formula (1) and formula (8), and the output waveform of M2 is the product of formula (2) and formula (8). After the product and difference operation, the final output signal is obtained: ; (9) Wherein, IbMP is the first mixed analog signal output by the analog multiplier M1; f1-f2 is the difference frequency component; and f1+f2 is the sum frequency component.

[0092] ; (10) Wherein, 1xMP is the second mixed analog signal output by the analog multiplier M2.

[0093] The difference frequency signal (f1-f2) = 10Hz is accurately set by DDS, as shown in formulas (6) and (7). The multi-channel AD synchronous conversion module U1 uses the ADS1278 chip, and the sampling rate is configured to be 40Hz. Its passband characteristic is 0.453×40=18.12Hz, which fully meets the sampling requirements of the 10Hz signal. The system cutoff frequency is set to 0.49×40Hz=19.6Hz. Since the test frequency of the embodiment of the present application is above 50Hz, the module attenuates the signal in this frequency band by more than 100dB, and its influence can be completely ignored. That is, the waveform of (f1+f2) is completely attenuated, =f1-f2 is set to 10Hz. Therefore, the signal waveform actually collected by the multi-channel AD synchronous conversion module U1 is shown in formulas (11) and (12). This design ensures the accurate extraction of the difference frequency signal and the effective suppression of high-frequency interference.

[0094]

[0095] Wherein, IbMP is the first low-frequency signal after filtering; is the phase difference between the standard current and the reference signal.

[0096]

[0097] Wherein, 1xMP is the second low-frequency signal after filtering.

[0098] The difference frequency test method adopted in the embodiment of the present application achieves high-precision broadband measurement through the signal processing mechanism shown in formulas (11) and (12). The system accurately tracks and sets a fixed difference frequency of 10 Hz, uses an analog multiplier to complete the multiplication operation of the two frequency signals, and outputs a composite signal containing the difference frequency (f1-f2) and the sum frequency (f1+f2). With the help of the high-performance anti-aliasing filter built into the multi-channel AD synchronous conversion module U1, the sum frequency (f1+f2) component can be effectively filtered out, retaining only the 10 Hz difference frequency signal for subsequent processing. Accurate measurement of the ratio difference and angular difference between the standard current and the current to be measured at any frequency f2 is achieved. The system sampling rate requirement is greatly reduced, and high-precision measurement can be completed with a sampling rate of only 10 Hz. In addition, through the coordinated optimization of analog domain preprocessing and digital domain filtering, the system power consumption and hardware cost are significantly reduced while ensuring measurement accuracy.

[0099] By synchronously sampling and demodulating the mixing signal IbMP, the amplitude and phase characteristic parameters of the standard current signal are accurately extracted:

[0100] Among them, IbA is the amplitude measurement result of the standard current signal after multi-channel AD synchronous sampling.

[0101]

[0102] in, This is the phase measurement result of the standard current signal after multi-channel AD synchronous sampling.

[0103] By synchronously sampling and demodulating the mixed signal IxMP, the amplitude and phase characteristic parameters of the current signal to be measured are accurately extracted:

[0104] Wherein, IxA is the amplitude measurement result of the current signal to be measured after multi-channel AD synchronous sampling.

[0105]

[0106] in, It is the phase measurement result of the current signal to be measured after multi-channel AD synchronous sampling.

[0107] Therefore, the wide-band current transformer ratio difference is:

[0108] It should be noted that the mixed signal amplitudes IxA and IbA both include the same proportional coefficient UrefA / 2, which is automatically offset during the ratio difference calculation process.

[0109] The angular difference of the wide-band current transformer is:

[0110] It should be noted that the influence of the reference signal phase φref is automatically eliminated by the signal processing algorithm, and only the relative difference between the phase φx of the current signal to be measured and the phase φb of the standard current signal needs to be accurately measured.

[0111] By comparing and analyzing the mathematical relationship between formulas (17)-(18) and formulas (3)-(4), it can be clearly seen that the core testing principle of the embodiment of the present application is that the system indirectly achieves high-precision testing of the amplitude ratio difference and phase angle difference of the original frequency f2 signal by accurately measuring the amplitude and phase characteristics of the difference frequency component (f1-f2).

[0112] The wideband current transformer test system provided in this application first uses a DDS chip with a built-in clock multiplier to track the measured signal frequency f1 in real time through a comparator and accurately generate a reference signal f2 = f1-10Hz. Secondly, an analog multiplier performs spectrum shifting to generate signals in two frequency bands: f1-f2 (10Hz) and f1+f2. The high-performance digital filter built into the Σ-Δ ADC then automatically filters out the sum frequency components, retaining only the 10Hz difference frequency signal for measurement. This achieves the goal of testing the high-frequency signal f1 by testing the low-frequency signal f1-f2 = 10Hz. High-frequency signal testing is indirectly achieved through low-frequency measurement, converting measurements of high-frequency signals of 100kHz and above to a fixed low-frequency measurement of 10Hz, breaking through the technical bottleneck of direct high-frequency signal sampling in traditional sampling systems. Thanks to the wideband characteristics of the DDS and analog multiplier (reaching over 100MHz), combined with a wideband current divider, accurate measurements of frequencies above 100kHz can theoretically be achieved, an order of magnitude improvement over the existing mainstream 10kHz test bandwidth. In addition, the system only needs a 40Hz sampling rate to process the 10Hz difference frequency signal, which greatly reduces the requirements for DSP processing power and performance. This makes the system low in power consumption (typical value <5W) and has obvious cost advantages, while ensuring measurement accuracy.

[0113] In one embodiment, a wideband current transformer testing device is provided, which corresponds to the wideband current transformer testing method in the above embodiment. Figure 3 As shown, the broadband current transformer testing device 100 includes: an acquisition module 101, a first generation module 102, a second generation module 103 and a determination module 104. The functional modules are described in detail as follows: An acquisition module 101 is configured to acquire a standard current signal, a current signal to be measured of a wide-band current transformer, and a first frequency signal of the standard current signal and the current signal to be measured; A first generating module 102 is configured to generate a second frequency signal based on the first frequency signal by using a frequency synthesis technique, wherein the second frequency signal is equal to a difference between the first frequency signal and a preset frequency difference; A second generating module 103 is configured to generate a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, and to filter out the sum frequency component in the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal; The determination module 104 is configured to determine a ratio difference and an angle difference between the current signal to be measured and the standard current signal based on the first low-frequency signal and the second low-frequency signal.

[0114] In one embodiment, the first generating module 102 is specifically configured to: Tracking the standard current signal through an analog comparator to generate a square wave signal synchronized with the first frequency signal; The square wave signal is input to the direct frequency synthesizer, and the system clock frequency signal is generated by the internal clock multiplication function of the direct frequency synthesizer; A second frequency signal is generated based on the system clock frequency signal and a preset frequency division setting value of the direct frequency synthesizer.

[0115] In one embodiment, the acquisition module 101 is further configured to: acquire a difference between the first frequency signal and the second frequency signal.

[0116] In one embodiment, the apparatus further comprises: A judgment module, used to judge whether the difference is equal to a preset frequency difference; The adjustment module is used to adjust the second frequency signal by adjusting the preset frequency division setting value if the difference is not equal to the preset frequency difference, until the difference between the first frequency signal and the second frequency signal is equal to the preset frequency difference.

[0117] In one embodiment, the second generating module 103 is specifically configured to: Based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, a first mixed analog signal and a second mixed analog signal are obtained by analog mixing technology, wherein the mixed analog signal includes a difference frequency component and a sum frequency component; The first mixed analog signal and the second mixed analog signal are converted into digital form, and the sum frequency component is filtered out based on a preset sampling rate to obtain a first low-frequency signal corresponding to the standard current signal and a second low-frequency signal corresponding to the current signal to be measured.

[0118] In one embodiment, the second generating module 103 is further configured to: multiplying the first frequency signal of the standard current signal by the second frequency signal to obtain a first mixed analog signal corresponding to the standard current signal; The first frequency signal of the current signal to be measured is multiplied by the second frequency signal to obtain a second mixed analog signal corresponding to the current signal to be measured.

[0119] In one embodiment, the second generating module 103 is further configured to: Decomposing the first mixed analog signal based on trigonometric identities to obtain a first difference frequency component and a first sum frequency component; Decomposing the second mixed analog signal based on trigonometric identities to obtain a second difference frequency component and a second sum frequency component; Performing analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal to generate a first digital signal and a second digital signal; Downsampling the first digital signal to a target rate through a digital filter, filtering out a first sum frequency component of the first digital signal, and outputting a digital signal corresponding to a first difference frequency component, which is recorded as a first low-frequency signal; Downsampling the second digital signal to a target rate through a digital filter, filtering out a second sum frequency component of the second digital signal, and outputting a digital signal corresponding to the second difference frequency component, which is recorded as a second low-frequency signal; The digital signal includes the amplitude and phase information of the difference frequency signal.

[0120] In one embodiment, the determination module 104 is specifically configured to: extracting a first amplitude and a first phase of the first low-frequency signal; extracting a second amplitude and a second phase of the second low-frequency signal; Calculating a ratio difference based on the first amplitude and the second amplitude; Based on the first phase and the second phase, an angle difference is calculated.

[0121] The present invention provides a wideband current transformer testing device 100, which first synchronously obtains the first frequency signals of the standard current and the current to be measured, tracks the frequency of the signal to be measured in real time through a high-speed comparator, and accurately generates a second frequency signal using digital frequency synthesis technology. Subsequently, the signal spectrum is shifted using analog mixing technology to generate a composite signal containing a difference frequency component and a sum frequency component. Finally, a high-order digital filter is used to accurately filter out the sum frequency component, and only the difference frequency signal is measured to obtain the ratio difference and angle difference parameters of the wideband signal. By converting the measurement of the wideband signal into the measurement of a fixed low-frequency signal, the technical bottleneck of direct sampling in the high-frequency band of traditional sampling technology is broken through, and the accuracy of the measured ratio difference and angle difference of the wideband current transformer is effectively improved. While ensuring the measurement accuracy, the system power consumption and hardware cost are significantly reduced, ensuring the reliability and accuracy of the wideband current transformer test in the smart grid.

[0122] The specific limitations of the broadband current transformer testing device can be found in the limitations of the broadband current transformer testing method described above and will not be further elaborated here. Each module in the broadband current transformer testing device described above can be implemented in whole or in part through software, hardware, or a combination thereof. Each of the modules described above can be embedded in or independent of a processor in an electronic device in hardware form, or stored in a memory in the electronic device in software form, so that the processor can call and execute the corresponding operations of each module.

[0123] In one embodiment, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned wide-band current transformer testing method is implemented.

[0124] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the wide-band current transformer testing method described above is implemented.

[0125] It should be noted that the above functions or steps that can be implemented by the computer-readable storage medium or electronic device can be referred to the relevant descriptions on the server side and the client side in the aforementioned method embodiment. To avoid repetition, they will not be described one by one here.

[0126] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the above-described method embodiments. Any reference to memory, storage, database, or other media used in the various embodiments provided herein may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct RAMbus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM).

[0127] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0128] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A broadband current transformer testing method, characterized in that: include: Acquire a standard current signal, a current signal to be measured of a wide-band current transformer, and first frequency signals of the standard current signal and the current signal to be measured; Based on the first frequency signal, generating a second frequency signal by frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference; generating a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal, and filtering out sum-frequency components from the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal; Based on the first low-frequency signal and the second low-frequency signal, a ratio difference and an angle difference of the current signal to be measured relative to the standard current signal are determined.

2. The method according to claim 1, characterized in that The step of generating the second frequency signal by frequency synthesis technology based on the first frequency signal specifically includes: Tracking the standard current signal through an analog comparator to generate a square wave signal synchronized with the first frequency signal; Inputting the square wave signal into a direct frequency synthesizer, and generating a system clock frequency signal through an internal clock multiplication function of the direct frequency synthesizer; The second frequency signal is generated based on the system clock frequency signal and a preset frequency division setting value of a direct frequency synthesizer.

3. The method according to claim 2, characterized in that After generating the second frequency signal based on the system clock frequency signal and the preset frequency division setting value of the direct frequency synthesizer, the method further includes: Obtaining a difference between the first frequency signal and the second frequency signal; Determining whether the difference is equal to a preset frequency difference; If the difference is not equal to the preset frequency difference, the second frequency signal is adjusted by adjusting the preset frequency division setting value until the difference between the first frequency signal and the second frequency signal is equal to the preset frequency difference.

4. The method according to claim 1, wherein The step of generating a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal, and filtering out the sum frequency component in the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal specifically includes: Based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, a first mixed analog signal and a second mixed analog signal are obtained by analog mixing technology, wherein the mixed analog signal includes a difference frequency component and a sum frequency component; The first mixed analog signal and the second mixed analog signal are analog-to-digital converted, and the sum frequency component is filtered out based on a preset sampling rate to obtain the first low-frequency signal corresponding to the standard current signal and the second low-frequency signal corresponding to the current signal to be measured.

5. The method according to claim 4, characterized in that The step of obtaining the first mixed analog signal and the second mixed analog signal by analog mixing technology based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal specifically includes: multiplying the first frequency signal of the standard current signal by the second frequency signal to obtain a first mixed analog signal corresponding to the standard current signal; The first frequency signal of the current signal to be measured is multiplied by the second frequency signal to obtain a second mixed analog signal corresponding to the current signal to be measured.

6. The method according to claim 4, characterized in that The step of performing analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal, and filtering out the sum frequency component based on a preset sampling rate to obtain the first low-frequency signal corresponding to the standard current signal and the second low-frequency signal corresponding to the current signal to be measured specifically includes: Decomposing the first mixed analog signal based on trigonometric identities to obtain a first difference frequency component and a first sum frequency component; Decomposing the second mixed analog signal based on trigonometric identities to obtain a second difference frequency component and a second sum frequency component; Performing analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal to generate a first digital signal and a second digital signal; downsampling the first digital signal to a target rate through a digital filter, filtering out the first sum frequency component of the first digital signal, and outputting a digital signal corresponding to the first difference frequency component, which is recorded as the first low-frequency signal; downsampling the second digital signal to a target rate through a digital filter, filtering out the second sum frequency component of the second digital signal, and outputting a digital signal corresponding to the second difference frequency component, which is recorded as the second low-frequency signal; The digital signal includes the amplitude and phase information of the difference frequency signal.

7. The method according to claim 1, characterized in that The step of determining the ratio difference and the angle difference of the current signal to be measured relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal specifically includes: extracting a first amplitude and a first phase of the first low-frequency signal; extracting a second amplitude and a second phase of the second low-frequency signal; calculating the ratio difference based on the first amplitude and the second amplitude; The angular difference is calculated based on the first phase and the second phase.

8. A broadband current transformer test device, characterized in that: include: An acquisition module, configured to acquire a standard current signal, a current signal to be measured of a wide-band current transformer, and first frequency signals of the standard current signal and the current signal to be measured; A first generating module is configured to generate a second frequency signal based on the first frequency signal by a frequency synthesis technique, wherein the second frequency signal is equal to a difference between the first frequency signal and a preset frequency difference; a second generating module, configured to generate a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal, and to filter out sum-frequency components from the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal; A determination module is configured to determine a ratio difference and an angle difference of the current signal to be measured relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the wide-band current transformer testing method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the wide-band current transformer testing method according to any one of claims 1 to 7 are implemented.

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